Abstract : Experimental groups attempted to reach consensus on the rank ordering of three proposals for a fictionalized new weapon system. Each member of the four-person group received information on whether or not the three proposed systems met each of 10 desired criteria for the new system. Information was provided to the groups in the form of a "hidden profile." That is, some of the information was known to all group members, while other information was known only to individuals in the group. The groups had to pool all relevant information, both common and unique, to reach a correct decision. The experimental variable was the meeting format: face to face, telephone conferencing, and electronic "chat" mode. As predicted, groups using the electronic "chat" mode made significantly fewer correct decisions, took more time to reach decisions, and experienced higher cognitive workload than the other two groups. Teleconferencing was the best communication mode for this information sharing problem. Collaboration technologies implemented in "groupware" formats need to consider information sharing and communication media as well as task type to maximize performance results, or to avoid undesirable group decision errors.